First, some background info: As many of you know, I recently completed my rebuild/upgrade (see: This Thread ). The primary function of the car is street/autocross use (with the occasional HPDE). As such, I switched to a simplified sequential 99spec setup (I've driven a few cars with a properly set up non-seq system, and I absolutely hated it. Also had no interest in single turbo). The simp-seq is nice, but still has a few annoyances. First, it still uses the stock solenoids (I had 2 fail since I finished the rebuild, and plenty before that). Second, since I removed the rack for the solenoids to attach to, the leftover hoses and valves created a complete mess under the UIM:

So I set out to learn more about solenoids and vacuum control systems so I could build an aftermarket system. Some may argue that there really is no advantage to this, but I figured that I might as well try it out and see what happens.

Basically, what I ended up building is a completely custom 5-solenoid setup (I'm running simplified sequential, so I only have the following solenoids: Purge Control, CCA, CRV, TCA (pressure), TCA (vacuum). These solenoids can be bolted together in almost any combination imaginable.

Even though these solenoids can take the heat of the engine bay, I decided that I was going to move them out from underneath the UIM. Couple of reasons for that: It will help move some heat-storing mass away from that area (hopefully helping out the coils, fuel system, and intake manifold). It's a little easier to get to the vacuum lines/solenoids for diagnosis. And lastly, I think it gives it a slightly cleaner look.

I decided to place the solenoids next to the passenger fender, right behind the ABS system. There is just enough room for the solenoids in this location, and the lines aren't any longer than they were when the solenoids were under the UIM. The only modification needed, was that the wires for the airbag had to be unbolted from their bracket and lowered slightly. After that, the solenoid rack dropped right in.

Here are a few preliminary mock-ups of what it'll look like when I'm completely finished:

Testing of this system will begine shortly (later this week, after the snow has melted). I'll post any and all results.

I've considered doing something similiar, but I was stymied trying to find a suitable replacement solenoid - looks like you found a winner!

You could almost do something approaching the '96+ solenoid "black box" that Mazda went to. It has less inputs and internally split the signals in molded plastic pathways, bigtime simplifying things. If you think about it, there's only a few inputs, but the inputs get split to different solenoids, etc.

Something like this could also be possible with the stock solenoids - moving them to that location would remove them from their heat source, and in a way moves them closer to what they're supposed to be controlling - the turbos themselves.

Coming from a 3 month journey on fixing my sequential system, I know how difficult the turbo system is to work on. I am very impressed by the progress you have made on your project -- I hope the solenoid rack works.

WOW! Looks great. You make me wish I had not done a new hose job last spring. Still, this should make things way easier to diagnose. Keep us up to date when you road test. Then a writeup on the solenoids would be great.

J.S.J did something similar to his car a few months back. However, he created a boost problem in doing so and I never read that he fixed the problem (and I believe he recently sold his car).

Looking forward to hearing your results. Hopefully you'll have some better luck than J.S.J did with his project.

Thanks for the heads-up. Now that you mention it, I vaguely remember hearing about J.S.J's project, although I never really heard any details or results. I did a quick search after you mentioned this to find some info. It appears that what he did was reuse the stock solenoids, and move them to the drivers fender (where the cruise control is located on Touring models). The only advantage that I see to this is that the solenoids are easier to access for fault-diagnosis. But the system still uses the stock solenoids (of which, I am not a big fan), and they are now located 2-3 times farther away from the turbos than the stock setup. As I understand, he did have a boost problem (only getting 7psi throughout RPM range), and I'm not sure if he ever corrected it.

I've considered doing something similiar, but I was stymied trying to find a suitable replacement solenoid - looks like you found a winner!

You could almost do something approaching the '96+ solenoid "black box" that Mazda went to. It has less inputs and internally split the signals in molded plastic pathways, bigtime simplifying things. If you think about it, there's only a few inputs, but the inputs get split to different solenoids, etc.

Something like this could also be possible with the stock solenoids - moving them to that location would remove them from their heat source, and in a way moves them closer to what they're supposed to be controlling - the turbos themselves.

Keep us posted on your progress! I'm eatin' this up!

Dale

Thanks Dale!

I actually considered trying to get my hands on a 96+JDM solenoid unit to test. There were a couple of things preventing me from doing this though. 1) the unit is one gigatic box. Wiring it would be a pain, as would diagnosing any problems. 2) Any small failure of an internal portion would require replacement of the entire system. 3) I'm not positive of the make-up of the internals. If I am going through the trouble to do this, I wanted to be sure than the equipment is better than stock. 4) Not easy to get my hands on one, and it would probably be $$$ if I could.

I also contemplated using the stock solenoids as you mentioned (similar to what J.S.J did). But again, if at all possible, I wanted the equipment to be of better quality than the stockers. I was also looking for something a little cheaper, as buying brand new solenoids from the dealer is fairly expensive.

That looks awesome!!! By any chance do you have a write up on how do make the seloniods? I would be interested. And roughly what it cost you to make the whole kit.

Actually, most of these components were produced locally and can only be aquired through an authorized distributor. Fortunately, I just happen to be one of those "authorized distributors." Once I get this system up and running, and I complete thorough tests to verify that it'll meet requirements, I will consider building these and distruting them to anyone interested. Keep in mind that I can custom design and produce virtually any system you want. So whether you want an entire rack of 12 solenoids, or only 4, if can easily be done.

This particular prototype probably cost about $275 to build (maybe a little more). For the final versions, you can estimate about $45-50 per solenoid.

I actually considered trying to get my hands on a 96+JDM solenoid unit to test. There were a couple of things preventing me from doing this though. 1) the unit is one gigatic box. Wiring it would be a pain, as would diagnosing any problems. 2) Any small failure of an internal portion would require replacement of the entire system. 3) I'm not positive of the make-up of the internals. If I am going through the trouble to do this, I wanted to be sure than the equipment is better than stock. 4) Not easy to get my hands on one, and it would probably be $$$ if I could.

I also contemplated using the stock solenoids as you mentioned (similar to what J.S.J did). But again, if at all possible, I wanted the equipment to be of better quality than the stockers. I was also looking for something a little cheaper, as buying brand new solenoids from the dealer is fairly expensive.

-Rob

I considered doing a conversion to the '96+ black box, but one big thing stopped the process - I noticed that the black box has the cheesy stock check valves BUILT-IN. I'm not sure if it's replaceable or not, either.

I attached 2 pics - one of which you can clearly see a stock check valve. I do like how it has common "manifolds" feeding the solenoids - pretty slick.

Dale, another concern I would have is whether or not the 16bit ecu has any control over the box (I'm pretty sure it does). With that, I would really question whether or not it would even work with our ecu.

To ensure you don't have any funny boost results, I suggest comparing the new length of vacuum line to the stock lengths. Making the hose lines too long could cause delayed responses of the solenoids and actuators. Substituting portions of hard pipe might work well.

Dale, another concern I would have is whether or not the 16bit ecu has any control over the box (I'm pretty sure it does). With that, I would really question whether or not it would even work with our ecu.

The ECU definitely has control over the black box, but it's logical to assume that the box is just simple 12v on/off solenoids, much like our individual solenoids. It's *possible* that it could be controlled by the '93-95 ECU, but there's so many "what if's", not to mention the fact that the black box just simply seems to have longevity problems. I'd much rather swap one solenoid out that's bad than try and hunt down another good black box if it failed!

Actually, most of these components were produced locally and can only be aquired through an authorized distributor. Fortunately, I just happen to be one of those "authorized distributors." Once I get this system up and running, and I complete thorough tests to verify that it'll meet requirements, I will consider building these and distruting them to anyone interested. Keep in mind that I can custom design and produce virtually any system you want. So whether you want an entire rack of 12 solenoids, or only 4, if can easily be done.

This particular prototype probably cost about $275 to build (maybe a little more). For the final versions, you can estimate about $45-50 per solenoid.

-Rob

Rob, I'm interested, esp. if these solenoids can resist 15psi and not STICK. I replaced my charge control solenoid, and it still sticks periodically under high-boost, so I have little power. . .